Motor-cycle frame



1 06,995 Patented June 17, 1919.

G. E. BRADSHAW.

MOTOR CYCLE FRAME. APPLICATION FILED SEPT-19.1918.

GRANVILLE rnnsrwfjoon BRADSHAW, or HERSHAJVI, wa ron-oiv-THA Es, ENGLAND,

ASSIGN OR OF O'NE- HA LF A. B C. MOTORS LIMITED, F HERSHAM, WALTON-ON- ENGLAND-,1

To all whom it may concern:

Be itknown that I, GRANVILLE E'Asrwoon 'BRAosHAw, a subject of the King of" Great Britain and Ireland, of A513. 0. Motor WVorks, Hersham, lValton-on-Thames, in the county of Surrey, England, have invented new and useful Improvements in Motor- Gycle Frames, of which the following isa specification. V

In motor cycles wherein the engine is .bolted rigidly to the frame, and the rear wheel supported fromthe side frame by means of springs, if, for example, thesystem of power transmission is by'chain, the

the. engine and joints engine ordinarily pulls on the top side of the chain.;:-It presents the disadvantage, therefore, that as the back" wheel rises, it moves the top part of the chainslightly in the'di-rection inwhich the engine is pulling, and lessens the load. Conversely the rear wheel falls, thereis a pull in the cliainfin the reverse direction, and a snatch occurs which upsets. the evenness of the drive. When the power transmission is by shaft, a flexible coupling is usually necessary with the existing arrangements for springing the vehicle. Now, according to my invention gear box are able to rock slightly to and fro, keeping the shaft free from stress, or the chain at a constant tens sion. The same result applies to bevel or worm transmission.- a

My improvements are especially applicable to those motor cycles wherein the power of the engine hasto be transmitted through shafts. or chains, or any other 'known gearing, to wheels supported from the main frame by springs which lessen the shocks due to uneven-road surfaces.

My invention enables universal or sliding joints to be dispensed with, for instance, in the case of a shaft-driven cycle; neither is it necessary to have radius rods with hinge or sliding connections, nor is it imperative to have shackles or shackle bolts on the springs, although any of these may be fitted if desired. Also I gain a further advantage in that the springs can be carried in 'such a manner that they are removed some distance away from the road wheels, and can more readily be protected from dust and mud.

My invention furthermore reduces to a minimum the amount of unsprung weight,

.ivroroR-o o E FRAME.

Specification of Letters Patent.

of the vehicle, instead of on the axle,

Reference will hereinafter be made to the accompanaying drawings, illustrating a convenient example of my said invention, and to the reference numerals thereon. Figure 1 is a side elevation of a motor cycle, and Fig. 2 a vertical section throughthe crank case. p v p v The engine 4 is-not, asin ordinary motor cycle practice, carried on the mainframe, but on the'sub-frame 2, or any suitable part of the main frame 3, or an extension thereof.

The engine 4 will thus rock slightly forward and backward as therear wheel 9 rises and falls on the surface of the road. This does not have any detrimental effect, compared with previous forms because even .when the engine was fitted to the sprung i 'rough roads, due to the reaction of the springing. This remark applies also to a gear box 17 if used, which can be mounted on the sub-frame 2.

Leaf springs 10 of the type known as quarter-elliptic, are shown as examples, the thick end of the spring being bolted to the main frame 3 (which therefore bears its weight) and the thin end working between rollers mounted on pins 12 fixed in a box 5 formed integral with the upright member of the sub-frame 2 (or alternatively shackles could be used) in such a manner as to prevent relative lateral movement between the main frame 3 and the sub-frame 2; this removes stress or pressure from the transverse joint described below when the vehicle is traveling around corners. The

Patented. June 17, 1919. Application fi1ed;September 19, 1918. Serial N 0. 254,811. i

springs 10 could bear directly or indirectly upon the rear wheel axle instead of on the sub-frame, if preferred. They are two in number, one on each side of wheel 9.

, The transverse joint may be a roller 'or ball bearing, and it may be connected to the oiling system in the engine or gearbox, or pass through the engine or to be efficiently and automatically lub-ricated.

The transverse joint which is illustrated in the figures, comprises a bolt 19 adapted to tighten in a bush 6 (Fi 2) which passes through the crank case 16, where it is constantly lubricated by oil in the crank case gearbox so as j penetrating throughoil ;ho'les';; but, if any objection should be made to this position on the ground that it throwsi unduefltorque stress up'on the crank case. 16, for example, the joint could easily be located outside the crank case and lubricated in any other manner, or it could remain in the crank case rigid with the sub-frantic.

it is inclosed in artube 18 extending from vthe eng ne 4' to the rear axle casing 15; the

tube 18 isalso integral with the sub-frame 2 and may be braced to any part of it for increasing the strength of same, and for Withstanding the torque exerted by the drive. It might even form the entire or partial connection between the rear axle l and the transverse joint, or any part of it,

and there could be attached to it any suitable extension or connections forcarrying the springs, or any other fitments that may be desired. a

Petrol, oil, and water pipes may be fitted with flexible connections if they, are re quiredto connect between the sub-frame and the main frame, and the, nearer the center of Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents', V

. mass of .'tl1e e ngine and gearbox islplaced to the transverse 01111;, the smaller is the amount of energy required to rock them to and fro, and smaller also isthe relative movement of suchpart's. I

render them easily protectable lay-covers of =metal,or anyfiexible material. p 40" I claim 7 '1. In a motorcycle, a ma1nframe, a sub;

frame fulcrumed on the main frame and '7 supporting the rear wheelof the 'motorcycle, a vertical extension on the rear-end of thes'ub-frame, a leaf spring pivotedqto the main frame and having a sliding con- 'neetion with the extension, amotor fixed to the sub-frame at -its fulcrum T point, 'anda;

driving connection between the rearwheel .and the-moton' A v 2. In a motorcycle, adnain frame, 7 a motor mounted on the main frame, al sub- 2:: .frame carried by the rear axle and having a pivotal connection at its forward end with the main, frame, said connectionvcomprijsr ing lugs on thesub-frame, a bolt extending through said motor and sa d lugs,- and a bushing surroundmgthe bolt.

GRANVILLE EASTWOOD BRitsHiWI.

Washington, D. 0

. V 35 The front springing and steerifng connec- V V 'tions may be of any known type, and: the i 7 rear springs may be so placed or fitted as to 

